This invention relates to electric motors and, more particularly, to permanent magnet single air gap electric motors.
In our prior U.S. Pat. No. 3,891,876, issued June 24, 1975, there is disclosed a single air gap permanent magnet electric motor having a single solid non-magnetic armature with commutated windings thereon mounted for rotation centrally in a single air gap formed between opposed pairs of permanent magnets having oppositely polarized flat or convex poles facing the armature. Sufficient air gap flux is provided through the use of rare earth alloy magnets. Although this prior disclosed motor has superior operational characteristics over those of conventional permanent magnet motors, the use of rare earth alloy magnets substantially increases the cost of such a motor. It would therefore be desirable to utilize low cost magnets such as ceramic magnets. However, the magnetic flux density provided by ceramic magnets of conventional configuration is not great enough for use in a single air gap permanent magnet motor.
It is therefore an object of this invention to provide an arrangement whereby ceramic magnets may be utilized to provide adequate flux density for use in a single air gap permanent magnet motor.